Do not wrap into an Apply in ensureApplied if a type parameter is expected

Author: jchyb

compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala

@@ -485,7 +485,8 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
         def appliedToNone: Apply =
           self.appliedToArgs(Nil)
         def ensureApplied: Term =
-          if (self.tpe.widen.isParameterless) self else self.appliedToNone
+          def isParameterless(tpe: TypeRepr): Boolean = !tpe.isInstanceOf[MethodType]
+          if (isParameterless(self.tpe.widen)) self else self.appliedToNone
         def appliedToType(targ: TypeRepr): Term =
           self.appliedToTypes(targ :: Nil)
         def appliedToTypes(targs: List[TypeRepr]): Term =

library/src/scala/quoted/Quotes.scala

@@ -890,7 +890,7 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
         /** The current tree applied to (): `tree()` */
         def appliedToNone: Apply
 
-        /** The current tree applied to `()` unless the tree's widened type is parameterless */
+        /** The current tree applied to `()` unless the tree's widened type is parameterless or expects type parameters */
         def ensureApplied: Term
 
         /** The current tree applied to given type argument: `tree[targ]` */

tests/pos-macros/i23969/Macro.scala

@@ -4,6 +4,8 @@ import scala.quoted._
 object TestMethods:
   def a1 = ()
   def a2() = ()
+  def a3[T] = ()
+  def a4[T]() = ()
 
 transparent inline def runMacro() = ${runMacroImpl}
 def runMacroImpl(using Quotes): Expr[Any] =
@@ -16,6 +18,19 @@ def runMacroImpl(using Quotes): Expr[Any] =
   Select.unique('{TestMethods}.asTerm, "a2").ensureApplied match
     case Apply(_, _) =>
     case _ => assert(false)
+  Select.unique('{TestMethods}.asTerm, "a3").ensureApplied match
+    case Select(_, _) =>
+    case other => assert(false)
+  Select.unique('{TestMethods}.asTerm, "a4").ensureApplied match
+    case Select(_, _) =>
+    case other => assert(false)
+
+  TypeApply(Select.unique('{TestMethods}.asTerm, "a3"), List(TypeTree.of[Nothing])).ensureApplied match
+    case TypeApply(_, _) =>
+    case other => assert(false)
+  TypeApply(Select.unique('{TestMethods}.asTerm, "a4"), List(TypeTree.of[Nothing])).ensureApplied match
+    case Apply(_, _) =>
+    case other => assert(false)
 
   // regression test
   val Inlined(_, _, generated) = '{BigDecimal(0).toString()}.asTerm : @unchecked